Red Supergiants
in the Inner Galaxy:
an infrared spectroscopic search
Maria Messineo
University of Science and Technology of China
Coauthors:
(USTC -Hefei)
Don Figer (RIT)
Karl Menten (MPIfR)
Rolf Kudritzki (IfA)
Rosie Chen (MPIfR)
Valentin Ivanov (ESO)
Zhu Quingfeng (USTC)
Special thanks to:
Harm Habing (Leiden), Ed Churchwell (Wisconsin-Madison
Univ.), Ben Davies (LJMU)
Canberra, 2016-11-22
Red Supergiants
What:
Where:
Stars > 8 Msun
Fate: BH or NS
initial mass, Z, Winds, rotation, B
in Clusters/Associations
isolated ?
Massive stars
Why:
Galactic structure (e.g. spiral arms)
ISM-metallicity
ISM-shapers
Distance indicators
Credit: Robert Hurt, IPAC; Bill Saxton, NRAO/AUI/NSF
Norma
Perseus
5 RSGCs
Sagittarius
1 RSGCs
Scutum-crux
Based on: GLIMPSE & Bessel results
A infrared stellar cluster rich in RSGs: RSGC1
14 RSGs
GAP
Images: 2MASS
Figer et al. (2006)
Color selection 1
Q1 =(J−H)−1.8×(H−Ks); Q2 =(J−Ks)−2.69×(K−[8.0])
Messineo M, Menten K.M., Churchwell E., Habing H., 2012 A&A, 537,10
Color selection 2
Q1 =(J−H)−1.8×(H−Ks); Q2 =(J−Ks)−2.69×(K−[8.0])
• Q1 = 0.1 – 0.5
• Q2 = 0.5 – 1.5
GLIMPSE NorthI-2MASS catalog
• Ks < 7 ~9000 stars
• Aks > 0.4 mag
•  Mbol < -6.1 for 4 kpc
i.e. Ks< 4+Aks
~130 stars of which 94 were
spectroscopically observed
Messineo M., Zhu Q., Menten K.M., Ivanov V.D., Figer D.F., Kudritzki R.P.,
Chen C.-H. R. (2016, ApJ, 822, 5)
Water index is defined as in Blum et al. 2003, ApJ, 597,323
(l,b) distribution
Targets
Known:
Skiff &
Negueruela et al &
Figer et al &
Davies et al.
Messineo M., Zhu Q., Menten K.M., Ivanov V.D., Figer D.F., Kudritzki R.P.,
Chen C.-H. R. (2016, ApJ, 822, 5)
Current distances from clump stars
2MASS/UKIDSS K vs J-K diagrams
RESULTS
Observed 94 targets (10 < l < 65 deg, |b|<1deg)
• 58 of them are spectroscopic RSGs
(no water and EW(CO) > 45 Angstroms).
• for 68 of them distances are obtained with clump stars.
• Heliocentric distances: 3.6 to 8.6 kpc.
• Galactocentric distances: 2.5 to 7.6 kpc.
• Luminosities: 3.2 x 10^4 to 1.3 x 10^5 Lsun
This is an increase of at least +25% (64) in the number of
previously known RSGs in the searched area.
Arms: Lazio & Cordes 2001
Luminosities
Ekstroem et al 2012
Chieffi et al. 2013
Messineo M., Zhu Q., Menten K.M., Ivanov V.D., Figer D.F., Kudritzki R.P.,
Chen C.-H. R. (2016, ApJ, submitted)
Future
Observed – To be observed
THANK YOU
to all of you